For example, there is a network monitoring apparatus that captures a packet that passes, for example, a switch by mirroring to monitor the state of a network.
Specifically, in addition to a method in which sequenced packets are analyzed and statistical processing for the number of packet losses, round trip time (RTT), and the like is performed based on an analysis result to thereby promptly analyze the state of a connection, there is a method in which captured packets are accumulated and the state of connection is retroactively analyzed.
When an error occurs in a connection, without accumulated packets relating to the connection, the contents of the error are not retroactively analyzed. However, if packets relating to connections are accumulated in order to enable retroactive analysis for any of the connections, the storage capacity that is to be provided is increased. Japanese Laid-open Patent Publication No. 2010-178299 and Japanese Laid-open Patent Publication No. 2008-060672 discuss related art.